Machine tools commonly mount a plurality of rotating tool spindles in close relationship to each other wherein a plurality of tools, drills, for instance, may be simultaneously rotated and axially displaced to drill a plurality of holes in a pattern determined by the location of the tool spindles. As the tools must be periodically replaced for sharpening, or other reasons, various types of chucks and tool holders are employed with the spindles to releasably hold the tool within the spindle in an accurate manner.
When the tool spindles are located in a concise pattern and there is little clearance between adjacent spindles, the configuration and dimensions of the chucking and tool holding apparatus becomes significant as the minimum spacing between adjacent tools may be largely determined by the space required by the tool holding apparatus. Tool holders for use with rotatable spindles have been developed which are of a concise configuration and yet are capable of firmly locating and holding a tool, or the tool adapter, within the spindle socket. Concise tool holding arrangements for use with spindles are shown in U.S. Pat. No. 3,720,417 and 4,395,051.
While concise spindle tool holder chucking and holding devices are known, it is often desirable to simultaneously change or replace a plurality of tools which are closely oriented to each other in a predetermined pattern, and the close proximity of adjacent tool spindles renders the operation of the tool releasing and latching apparatus difficult and time consuming, and the proximity of adjacent tool spindles complicates tool changing and replacement procedures.
It is an object of the invention to provide a quick release tool holder system for a machine tool wherein the tools are concisely related to each other with a minimum of clearance between adjacent tools and spindles.
A further object of the invention is to provide a quick release tool holder system for machine tools wherein a plurality of rotating tool spindles concisely oriented to each other and each utilizing a separate releasable tool holder may be simultaneously actuated to permit simultaneous tool replacement in a short duration of time.
Yet another object of the invention is to provide a quick release tool holder system for machine tools wherein a plurality of concisely oriented rotating spindles are mounted upon a rotatable head each employing a tool holder wherein the tool holders of adjacent spindles may be simultaneously released by a motor stationarily mounted with respect to the rotating head.
In the practice of the invention a machine tool includes a head rotatable about an axis. A plurality of tool stations are mounted upon the head wherein the head may be indexed about its axis to sequentially present the tool stations in alignment with a workpiece for machining purposes. Each tool station includes a plurality of spindles rotatably mounted upon the head in parallel relationship to each other and in a predetermined pattern. Each spindle includes an outer free end having a socket defined therein for receiving a standard tool adapter in which is mounted a tool, such as a drill, reamer, or the like.
Each spindle includes tool holder or chuck apparatus adjacent its outer end for retaining the tool adapter within its socket. This tool holding apparatus, in accord with the invention, includes a radially movable detent mounted upon the spindle displaceable into the spindle socket for locking engagement with the tool adapter by a cam surface defined on a cylindrical sleeve reciprocably mounted on the spindle exterior. A spring mounted on the spindle biases the sleeve in a direction forcing the detent into engagement with the tool adapter for retaining the adapter within the spindle socket, and upon movement of the sleeve in the opposite direction toward the spring, the detent releases the adapter and permits the adapter to be readily pulled from the spindle socket.
In accord with the invention, all of the detent operating sleeves of a tool station may be simultaneously translated in the tool adapter releasing direction, and held in the tool adapter releasing position permitting all of the tools to be readily replaced and changed.
Simultaneous actuation of the spindle sleeves is by an actuator plate disposed perpendicular to the length of the spindles having openings therein for receiving the spindles, but the dimension of the openings is less than the diameter of the sleeves. The plate is located adjacent the outer end of the sleeves and is mounted on an actuator shaft reciprocably mounted within the machine tool head and connected at its inner end with a linear motor for axially translating the shaft. Movement of the actuator plate in the direction of the sleeves abuts the plate against all of the spindle sleeves at the tool station simultaneously displacing the sleeves to the tool release position. The plate will hold the sleeves in this position and the tools and tool adapters may be readily removed from the spindle sockets.
The removed tool adapters and tools are replaced with sharpened tools mounted within the adapters, and the same are inserted into the spindle sockets. The linear motor translates the shaft and actuator in the opposite direction permitting the sleeves to be biased toward the tool holding position by springs associated with each sleeve, and in this manner all of the spindles at a common station are simultaneously restored to an operative condition, and the normal machining cycle of the apparatus continued.
In accord with the invention, the movement of the actuator shaft is by the reciprocating piston of an expansible chamber motor. To simplify installation, the motor is mounted upon a fixed portion of the machine tool fixed relative to the head wherein the head rotates relative to the motor. To interconnect the actuator plate shaft and the motor piston, a coupling is mounted upon the shaft inner end which is received within a coupling mounted upon the piston upon the actuator shaft and piston becoming coaxially aligned during the rotative indexing of the head. Thus, the motor is only connected to the actuator shaft when the piston and shaft are in alignment, and a single motor may be used to operate the actuator plates of a plurality of tool stations.